Bad News on Sudden Oak Death

The Chronicle had an article today about the continued virulence of Sudden Oak Death in the Bay Area’s Oak Woodlands. In Marin, 53% of samples taken tested positive for the pathogen, a spike attributed to high rainfall the past couple years that helps SOD spread.

“We found that the number of positives were double and in some cases triple what they were last year,” said Matteo Garbelotto, the UC Berkeley forest pathologist who organizes the annual surveys. “We were surprised. That was a big jump.”

The findings are part of a major effort over the past four years to involve citizens in the battle against the mysterious pathogen, which has killed hundreds of thousands of oak trees from Big Sur to southern Oregon.

There are dire predictions of mass die offs of Coast and Black Oaks around the state. The Chronicle article suggests the following prevention measures:

— Remove bay trees near oaks; this increases the survival rate of oaks tenfold.

— Use phosphonate spray, which has proved to be effective against the disease.

— Avoid doing large-scale projects such as grading, soil removal or tree pruning in infected areas during the rainy season.

Another good preventative measure is to not plant host plants, such as Rhodys and Camellias in and around sensitive Oak areas.